Cell death induced in L-cells by treatment with thymidine: staging of the process and relationship to apoptosis

Biocompatibility of different barrier membranes in cultures of human CRL 11372 osteoblast-like cells: an immunohistochemical study

OBJECTIVE

The aim of this study was to evaluate the biocompatibility of two different barrier materials in cultures of human osteoblast-like cells (CRL 11372) in vitro.

MATERIAL AND METHODS

Polylactic acid (Epi-Guide; EG) and collagen membrane (Bio-Collagen, BC) were examined. To analyze the effect of materials on cell proliferation, cell numbers and cell viability, cells were cultured on the barrier membranes for 24 and 72 h. Cells plated on culture dishes (CD) served as positive controls. Cell proliferation rate was assessed by the bromodeoxyuridine (BrdU) immunohistochemical technique. The cell numbers of each well were counted. Cell viability was estimated by counting the number of cells, which excluded trypan blue solution. Scanning electron microscopy (SEM) was used to observe the interactions between osteoblastic cells and barrier membranes.

RESULTS

The highest number of BrdU-labeled cells were seen on CD after both of the time periods. In comparison with the other two groups, BC showed significantly fewer cells after both time periods. Regarding cell numbers, after 24 and 72 h of incubations CD showed the highest number of cells. The number of viable cells was similar for all the groups. After 72 h for the EG group, SEM view showed flat cells. After 72-h time periods, the BC group revealed a weak adhesion of cells to the barriers.

CONCLUSION

The results demonstrate that cells were able to proliferate on these materials and EG promoted the proliferation of human osteoblast like cells. We prefer to use the EG membrane.

The effects of naproxen sodium on specific parameters of L-strain cells over guided bone regeneration barrier materials

There is strong evidence that nonsteroidal antiinflammatory drugs (NSAID) may exert a significant antiproliferative effect. This study evaluated the influence of NSAID on specific parameters of fibroblastic cells, in vitro, over two-guided bone regeneration (GBR) barrier materials. Fibroblast cells were cultured on bioabsorbable membrane made of collagen (Bio-Gide(R)- BG) and the most common nonresorbable membrane which is made of expanded polytetrafluoroethylene (ePTFE, Gore-Tex(R)- GT). Naproxen sodium (10 mM) was used as an analgesic drug. The fibroblast cells were cultured in vitro for 24 h and examined by scanning electron microscopy (SEM). Cells were cultured in the presence of (3)H-thymidine to study cell proliferation. And also cell numbers and viabilities were measured. The difference between the means for each group were analyzed for statistical significance by Kruskal-Wallis one-way ANOVA followed by post hoc comparisons using the Dunn statistical method. Of all the six groups, the control group stimulated DNA synthesis more than the others. With respect to cell numbers, there was statistically significant difference between the control group and naproxen planted BG membrane group. The interpretation of our SEM images is that these two barriers and naproxen seem to have had the least effect on cellular morphology. These data suggest naproxen have an inhibitory effect on stimulation of DNA synthesis, cell numbers and viabilities. And also lacking adherence of cells to the membranes may be due to the physical properties of the materials.